1. Field of the Invention
The present invention relates to a power ratchet wrench, and more particularly to a power ratchet wrench having an enhanced structure.
2. Description of Related Art
With reference to FIG. 5, a conventional power ratchet wrench has a body (60), a planet gear device (50) and a mounting bracket (40).
The body (60) comprises an open end, a chamber, an inner surface, an inner thread and a drive device. The chamber is defined in the open end of the body (60). The inner thread is formed on the inner surface of the body (60). The drive device is mounted inside the body (60) and has a drive gear wheel. The drive gear wheel is rotatably mounted in the chamber of the body (60).
The planet gear device (50) is connected to the body (60) and has a connecting tube, three transmitting gear wheels and a rotating bracket. The connecting tube is securely connected to the open end of the body (60) and has an inner surface, an outer surface, an outer thread and multiple inner gear teeth. The outer thread is formed on the outer surface of the connecting tube and is screwed securely with the inner thread of the body (60). The inner gear teeth are formed in the inner surface of the connecting tube. The transmitting gear wheels are mounted in the connecting tube and are engaged with the drive gear wheel on the body (60) and the inner gear teeth of the connecting tube. When the drive gear wheel is rotated, the transmitting gear wheels are rotated with the drive gear wheel relative to the inner gear teeth of the connecting tube. Each transmitting gear wheel has a center and a mounting hole. The mounting hole is formed through the center of the transmitting gear wheel. The rotating bracket is rotatably mounted in the connecting tube, is connected with the transmitting gear wheels and has a center, a bottom, a gear wheel hole and three mounting posts. The gear wheel hole is formed through the center of the rotating bracket and corresponds to the drive gear wheel of the body (60). The mounting posts protrude from the bottom of the rotating bracket around the gear wheel hole and are respectively mounted in the mounting holes of the transmitting gear wheels. Accordingly, the rotating bracket is rotated by the rotation of the transmitting gear wheels.
The mounting bracket (40) is securely connected to the planet gear device (50) and the body (60) and has a proximal end, a distal end, a connecting segment (400), an upper clamping segment (401), a lower clamping segment (402), a mounting recess (403) and an operating device (41).
The connecting segment (400) is defined in the proximal end of the mounting bracket (40), is connected to the connecting tube of the planet gear device (50) with a C-ring and a screwed nut and has a center and a crank hole. The crank hole is formed through the center of the connecting segment (400) and communicates with the gear wheel hole of the rotating bracket. The clamping segments (401, 402) are respectively formed on the distal end of the mounting bracket (40) and are parallel to each other to form the mounting recess (403). Each clamping segment (401, 402) has a through hole (404, 405). The through holes (404, 405) are respectively formed through the corresponding clamping segments (401, 402) and communicate with the mounting recess (403).
The operating device (41) is mounted in the mounting bracket (40) and has a rotating crank (410), a drive ring (411) and a unidirectional operating shaft (416). The rotating crank (410) is rotatably mounted in the connecting segment (400), is connected to the rotating bracket of the planet gear device (50) and has an inner end, an outer end, an extending rod and a pushing block. The inner end of the rotating crank (410) extends through the crank hole of the connecting segment (400) and is engaged with the gear wheel hole of the rotating bracket of the planet gear device (50). The extending rod is formed axially and eccentrically on the outer end of the rotating crank (410). The pushing block is mounted around the extending rod. The drive ring (411) is mounted rotatably in the mounting recess (403) between the clamping segments (401, 402) and communicated with the through holes (404, 405), contacts the pushing block and has a curved end, an internal surface and multiple ratchet teeth. The curved end of the drive ring (411) contacts the pushing block. The ratchet teeth are formed on the internal surface. The operating shaft (416) is mounted in the through holes (404, 405) of the clamping segments (401, 402), is engaged with the ratchet teeth of the drive ring (411) and has an external surface, a bottom, multiple pawl teeth and a operating post. The pawl teeth are formed on the external surface of the operating shaft (416) and are engaged with the ratchet teeth of the drive ring (411). The operating post is formed axially on the bottom of the operating shaft (416) and is used to fasten or loosen a bolt or a nut. When the rotating crank (410) is rotated by the rotating bracket, the pushing block will push the drive ring (411) to swing to make the operating shaft (416) rotate. Then, a user can use the operating post to fasten or loosen a bolt or a nut.
However, the drive ring (411) and the operating shaft (416) are mounted in the mounting recess (403) by the clamping segments (401, 402). Consequently, all the force applied to turn the nut or the bolt is transmitted to the clamping segments (401, 402) and causes the clamping segments (401, 402) to be damaged quickly. Then, the drive ring (411) and the operating shaft (416) cannot mount securely in the mounting recess (403) to fasten or loosen a bolt or a nut.
The power ratchet wrench in accordance with the present invention mitigates or obviates the aforementioned problems.